Per README cannot install and use

Following the README at “Build”, I tried:
```
$ npm init @nutmeg hello-world name:string
npx: installed 139 in 13.399s
error: unknown command 'hello-world'. See 'create --help'.
```

I also tried:
```
$ npm install @nutmeg/cli
(it works)
$ nutmeg new hello-world name:string
-bash: nutmeg: command not found
```
What's the correct incantation to install and use Nutmeg? Looking forward to trying it.